What is the purpose of the “role” attribute in HTML?

I keep seeing role attributes in some people’s work. I use it too, but I’m not sure about its effect. For example: <header id=”header” role=”banner”> Header stuff in here </header> Or: <section id=”facebook” role=”contentinfo”> Facebook stuff in here </section> Or: <section id=”main” role=”main”> Main content stuff in here </section> Is this role attribute necessary? Is … Read more